You should not eat sour cream left out overnight.
Sour cream spoils within 2 hours of being left out at room temperature.
If you left sour cream out at room temperature overnight then it will certainly have bacteria in it and will usually smell bad or have mold growth in it.
Sour cream left out overnight or longer than a few hours should be thrown out to prevent getting sick.
Any dairy products that are left out longer than 2 hours are likely bad and should be thrown out.
If kept at temperatures above 40 °F, sour cream will rapidly develop signs of spoilage; sour cream should be discarded if left for more than 2 hours at room temperature.
Signs that your sour cream are bad include.
Mold, discoloration, or significant change of texture.
If there's lots or water in the container, or anything that's not supposed to be there, it's bad.
Sharp sour or funny smell.
Off taste.
If your sour cream is a little watery on top, it's okay to eat.
But if there's a lot of water, it smells sourer than usual, or there are any other signs of spoilage, throw it out.
Because sour cream is a dairy product, you can get sick from it rather easily if it isn't stored properly or goes bad.
Consuming expired sour cream can cause you to get food poisoning and may yield a variety of symptoms including nausea, stomach cramping, diarrhea, and much more.